Corteks proposes to develop a high speed, compact, moderately priced, magnetic neural stimulator for neurophysiology. The device will overcome major limitations of presently available magnetic stimulators by permitting restriction of stimulation to limited regions of neural tissue, and by allowing stimulation at higher rates. Major clinical applications will include diagnostic and intraoperative evaluation of efferent pathways, as well as possible in vivo selective fiber stimulation. The feasibility of stimulating restricted areas of neural tissue, and achieving high rates of stimulation was demonstrated in Phase I. In Phase II, we will perform experiments to determine optimum stimulation parameters, build an optimized stimulator, and test the device for both effectiveness and safety.